Phase 2 study of preoperative radiation with concurrent capecitabine, oxaliplatin, and bevacizumab followed by surgery and postoperative 5-fluorouracil, leucovorin, oxaliplatin (FOLFOX), and bevacizumab in patients with locally advanced rectal cancer: ECOG 3204.

BACKGROUND

Recent studies have demonstrated the feasibility of combining oxaliplatin with 5-fluorouracil (5-FU) or capecitibine and radiation therapy. The addition of bevacizumab to chemotherapy improves overall survival for metastatic disease. We initiated a phase 2 trial to evaluate preoperative capecitabine, oxaliplatin, and bevacizumab with radiation therapy followed by surgery and postoperative 5-FU, leucovorin, oxaliplatin (FOLFOX) and bevacizumab for locally advanced rectal cancer.

METHODS

Fifty-seven patients with resectable T3/T4 rectal adenocarcinoma were enrolled. Preoperative treatment was capecitabine (825 mg/m(2) twice daily from Monday to Friday), oxaliplatin (50 mg/m(2) weekly), bevacizumab (5 mg/kg on days 1, 15, 29), and radiation therapy (50.4 Gy). Surgery was performed by 6 weeks after neoadjuvant therapy. Beginning 8 to 12 weeks after surgery, patients received FOLFOX plus bevacizumab (5 mg/kg) every 2 weeks for 12 cycles.

RESULTS

Fifty-four of 57 enrolled patients were eligible. Forty-nine (91%) patients completed preoperative therapy and underwent surgery. Nine patients (17%; 90% confidence interval, 9%-27%) achieved pathologic complete response. Thirty-two patients (59%) experienced pathologic tumor downstaging, and 53% and 15% of patients experienced worst grade 3 and grade 4 acute toxicity, respectively. Forty-seven percent of patients who underwent surgery experienced a surgical complication.

CONCLUSIONS

The primary endpoint of a 30% pathologic complete response rate was not reached; however, the majority of patients experienced pathologic downstaging with this regimen. Increased wound-healing delays and complications may have been related to the addition of bevacizumab, oxaliplatin, or both. Continued observation of these patients will establish the long-term morbidity and efficacy of this combined modality approach.